Quantum Electron Clouds near Black Holes: Black Atoms and Molecules

We study quantum mechanical wavefunctions near highly curved spaces, i.e., black holes. By utilizing the formalism developed by DeWitt, we derive the Schr\"odinger equations in the vicinity of the Schwarzschild and the Reissner-Nordstr\"om black hole geometries. The quantum electron cloud for the "black hydrogen atom" - an electron trapped by black holes - is particularly studied. We solve the equations and find that black holes generally attract the wavefunctions, localizing them near the horizon where the electrons are most likely to be trapped. These results imply that not only classical objects but also the quantum material and even the chemical properties of the atoms are affected by strong gravity. We also discuss black hydrogen molecules composed of multi-centered Majumdar-Papapetrou black holes.